For years highways and airports have expanded vigorously to create substantial networks which link not only homes and towns to cities, but also countries to other countries. Trucking and airline industries have come to depend heavily on the highway and airport networks. The private automobile is also a heavy user of highways, as well as driveways and parking lots. In recent years inflation has caused the cost of highway and other such construction to increase dramatically. It is now and will be for many years politically and economically difficult to significantly add to either the highway or airport networks. Considering the dependency of both industry and the individual on these networks and the unlikelihood of substantial new construction, the age and level of maintenance of the various highway and airport surfaces takes on increased significance. Greater and greater amounst of highway and airport resources are going toward surface repair. Surface failures have become a monumental problem, a problem directly associated with poor jointing practices.
Many joint sealers have come on the market. Products like rubberized asphalt, silicone rubber, cold tar, PVC and neoprene are being used quite successfully. The selection of a proper sealer is contingent on the type of joint to be sealed and the end result desired. The end result, of course, is further determined by the adequacy of joint preparation and the method followed in applying the joint sealer. For example, consumers are commonly sold a sealant to paint over cracks in asphalt driveways. Although such sealant may cover over the crack for a few months, there is little lasting effect.
The highway industry recognizes that an old sealer must be removed from a crack, or if the crack is new, it must be widened to create a reservoir sufficient to accept a quantity of new sealant. The crack may be prepared by water blasting, routing, or sawing. A joint may be prepared using various known machines, such as single bladed saws on wheeled frames, smaller portable saws, diamond blade random crack routers, and carbide routers. Additionally, water jetting or blasting equipment is known. These various machines require water either as the blasting element or as a cooling element for a blade or router bit. U.S. Pat. No. 2,736,544 and U.S. Pat. No. 3,663,060 are exemplary of wheeled, single bladed saws for use in widening a random crack. Both patents show a cooling system for the blade which includes a mechanism for directing a stream of water onto the blade.
After widening, machines using a stream of water leave a large quantity of water remaining in the vicinity of the crack. It has become common to use more water to remove any slurry or foreign material from the crack. Thereafter, the crack must be allowed to dry before a sealant can be applied. A road must often be closed for several days in order to properly complete the procedure.
Since a large quantity of water is used both for cooling and for cleaning a widened crack, it is nearly a requirement that a water truck be available to supply water to the sawing or routing or water jetting equipment. In some locations, for example, driveways, parking lots, bridges and various highways where it is inconvenient to close large areas, the presence of a water truck is extremely inconvenient if not impossible.
Thus, the requirement for, and once available, the use of large quantities of water with known equipments present the highway and airport repair industry with particularly troublesome problems.